1. Field of Invention
The present invention relates to a method for adjusting settings of photographing a digital image, and more particularly, to a method for adjusting photographing settings of a digital camera through motion detection.
2. Related Art
With rapid development of digital cameras, many people record memorable moments through photographing. However, no matter for a film camera or a digital camera, due to instable holding of the camera by a user, a blurred image is usually generated during photographing. Hand shake problems to different extents exist in holding a camera by hands, and only each person has a different holding stability, causing involuntary displacement the instant a shutter is pushed. Therefore, in order to avoid blurring generated in a photographed image due to hand shakes, digital camera manufacturers correct blurred digital images through hardware or software.
For different digital camera manufacturers, different anti-shake mechanisms are added. A common anti-shake method is turning up photosensitivity (ISO), raising a shutter speed, or increasing an aperture value. All the various methods aim to reduce a shutter time during photographing, thereby reducing influences of hand shakes on digital images. However, all the methods have disadvantages. As for adjusting methods and hardware cost, adjusting photosensitivity is a cheaper method as compared with other methods. However, turning up photosensitivity generates larger noises, such that an imaging quality of a digital image is decreased. Adjusting the shutter time and the aperture value decreases an amount of light entering photosensitive components, so as to influence imaging brightness of the digital image.
In addition, factors influencing definition of a digital image further include motions of a photographed object. When the photographed object is shaking, if the object is photographed with a shutter time at a relatively low speed, the obtained digital image may be still a blurred image. Therefore, it is proposed to detect vibrations of a digital camera and shaking of a photographed object respectively at the same time. The photographing settings of the digital image is then compensated according to motion vectors of the two, thereby minimizing the causes influencing photographing.
In the prior art, a plurality of continuous mages are captured, and each pixel in the image is analyzed on camera vibrations or photographed object shaking according to the displacement in the continuous images. FIG. 1 is a schematic view of calculating pixels in a digital image in the prior art. The images at the upper left and the upper right in FIG. 1 are two continuous digital images 111, 112. Each pixel is analyzed, and motion changes of the camera and the photographed object may be effectively found (assuming that the photographed object is the human face in FIG. 1). In other words, the motion changes are the arrows at the lower part in FIG. 1. However, the calculation for all the pixels in the digital image causes an operational limit for digital cameras of common performances.